330 
Holden . — Observations on the 
the epicotyl below that point resembles an open gutter with its concavity 
towards the point of cotyledonary symphysis (Figs. 40-43). This condition 
characterizes the majority of those syncotyls in which there is partial 
suppression of the involved lateral cotyledonary bundles, and where the 
suppression is complete this is accompanied in many cases by a correspond- 
ing suppression of the first epicotyledonary leaf on the same side. As has 
been stated, however, the cotyledonary and epicotyledonary modifications do 
not synchronize exactly, so that complete suppression of the epicotyl leaf on 
the symphysis side may occur with a still persistent cotyledonary lateral, 
whilst a retention of the leaf in a reduced state may characterize a seedling 
in which the laterals have disappeared. Only one instance was observed in 
which compression affected the paired leaves of the second epicotyledonary 
node, and in this seedling, which was one with a single persistent lateral, the 
leaves of the first epicotyledonary node were practically normal in size, whilst 
the affected leaves were markedly reduced (Fig. 29). The behaviour of the 
vascular strands of the symphysis leaf was curiously aberrant, one of its 
lateral strands bifurcating and half fusing with the median strand to form 
a compound bundle situated close to one of the cotyledonary strands. This 
persisted for some time independently and ultimately died out, whilst the 
other half-lateral and the lateral on the opposite side formed the extreme 
members of the usual gutter-shaped system (Figs. 30-32). 
What may possibly represent the ultimate effect of compression on the 
epicotyledonary leaves is seen in some of the seedlings in which the cotyle- 
donary laterals on the symphysis side are completely suppressed. In these 
seedlings the number of leaves at the third cotyledonary node is reduced to 
two lying in what is normally the intercotyledonary plane (Fig. 49 ; cf. also 
Fig. 54). The vascular system of the one standing vertically above the 
persistent leaf from the first node behaves similarly to that occupying the 
same position in typical dicotyls, its median bundle bifurcating and the con- 
stituent halves uniting with the laterals of the basal leaf, whilst its laterals 
unite with the adjacent bundles from the leaves of the second node. The 
bundles of the other leaf from the third node unite with the adjacent 
laterals of the leaves of the second node, its midrib and one lateral fusing 
with one second node lateral, and its remaining lateral with the other. 
Their behaviour thus resembles that of the bundles of the leaf of the first 
node on the symphysis side in those seedlings in which it persists in 
a reduced condition (Figs. 51, 52 5 cf. also Figs. 54-59). 
The effects of progressively closer syncotyly may therefore be sum- 
marized as follows : 
A. Cotyledonary vascular system. 
(i) Modification of the lateral bundles on the symphysis side leading 
to their reduction, either simultaneously or otherwise, and their ultimate 
suppression. 
